Single tube loose buffer cables have been used to date in only limited applications, not including aerial and buried applications, because of their inherent low mechanical strength and poor temperature performance. The present invention allows these cables to be used in most duct, aerial and buried applications. Grooved spacer core cables have been used previously in duct applications as well as aerial and buried applications. However, the lack of suitable rigid tension elements in both of these constructions has limited the operating temperature range, the tensile strength and other mechnical properties of both of these cables.
Representative prior art would include U.S. Pat. No. 4,491,386 to Negishi et al. which discloses a grooved spacer core optical fiber cable and a process for producing the cable. The patent discloses providing an armor coating around the outer sheath of the cable for mechanical reinforcement. U.S. Pat. No. 4,239,335 to Stiles discloses providing at least one fiber with an elastomeric coating and then applying a fiber reinforced resin shell thereover. U.S. Pat. No. 4,534,618 to Bruggendieck and U.S. Pat. No. 4,318,588 to Zeidler et al. disclose optical communication cables utilizing glass fiber or spun yarns in a reinforced casing. Other patents of possible interest include U.S. Pat. No. 4,389,087 to Bendayan et al. and U.S. Pat. No. 4,365,865 to Stiles.
Although reinforced optical communication cables are presently known, applicant believes that the particular ruggedized loose buffer tube and grooved spacer core communication cable construction disclosed herein are unique and novel in the optical fiber communication cable technology.